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Bug#25471090: MYSQL USE AFTER FREE

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Description:- Mysql client crashes when trying to connect
to a fake server which is sending incorrect packets.

Analysis:- Mysql client crashes when it tries to read
server version details.

Fix:- A check is added in "red_one_row()".
This commit is contained in:
Arun Kuruvila 2018-02-12 15:19:43 +05:30
parent e585decb45
commit e4784703ee
3 changed files with 46 additions and 10 deletions
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3
include/mysql_com.h
View File

@ -1,4 +1,4 @@
/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
/* Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -561,6 +561,7 @@ void my_thread_end(void);
#ifdef _global_h
ulong STDCALL net_field_length(uchar **packet);
ulong STDCALL net_field_length_checked(uchar **packet, ulong max_length);
my_ulonglong net_field_length_ll(uchar **packet);
uchar *net_store_length(uchar *pkg, ulonglong length);
#endif

16
sql-common/client.c
View File

@ -1,4 +1,4 @@
/* Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
/* Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -1723,18 +1723,20 @@ read_one_row(MYSQL *mysql,uint fields,MYSQL_ROW row, ulong *lengths)
end_pos=pos+pkt_len;
for (field=0 ; field < fields ; field++)
{
if ((len=(ulong) net_field_length(&pos)) == NULL_LENGTH)
len=(ulong) net_field_length_checked(&pos, (ulong)(end_pos - pos));
if (pos > end_pos)
{
set_mysql_error(mysql, CR_UNKNOWN_ERROR, unknown_sqlstate);
return -1;
}
if (len == NULL_LENGTH)
{ /* null field */
row[field] = 0;
*lengths++=0;
}
else
{
if (len > (ulong) (end_pos - pos))
{
set_mysql_error(mysql, CR_UNKNOWN_ERROR, unknown_sqlstate);
return -1;
}
row[field] = (char*) pos;
pos+=len;
*lengths++=len;

37
sql-common/pack.c
View File

@ -1,5 +1,4 @@
/* Copyright (c) 2000-2003, 2007 MySQL AB
Use is subject to license terms
/* Copyright (c) 2000, 2018 Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@ -46,6 +45,40 @@ ulong STDCALL net_field_length(uchar **packet)
return (ulong) uint4korr(pos+1);
}
/* The same as above but with max length check */
ulong STDCALL net_field_length_checked(uchar **packet, ulong max_length)
{
ulong len;
uchar *pos= (uchar *)*packet;
if (*pos < 251)
{
(*packet)++;
len= (ulong) *pos;
return (len > max_length) ? max_length : len;
}
if (*pos == 251)
{
(*packet)++;
return NULL_LENGTH;
}
if (*pos == 252)
{
(*packet)+=3;
len= (ulong) uint2korr(pos+1);
return (len > max_length) ? max_length : len;
}
if (*pos == 253)
{
(*packet)+=4;
len= (ulong) uint3korr(pos+1);
return (len > max_length) ? max_length : len;
}
(*packet)+=9; /* Must be 254 when here */
len= (ulong) uint4korr(pos+1);
return (len > max_length) ? max_length : len;
}
/* The same as above but returns longlong */
my_ulonglong net_field_length_ll(uchar **packet)
{